1. Field of the Invention
The present invention relates to an apparatus for fabricating semiconductor device including a step of treating the surface of a semiconductor layer with hydrogen, and a method for fabricating semiconductor device including a step of treating the surface of the semiconductor layer with hydrogen. Particularly, the present invention relates to a method and an apparatus for removing a natural oxide layer from the surface of a silicon layer and moreover terminating the surface of the silicon layer using hydrogen, and a method for fabricating a semiconductor device including the above steps.
2. Description of the Related Art
The following are known as the existing methods for removing a natural oxide layer from the surface of a semiconductor wafer and hydrogen-terminating the surface of the semiconductor wafer: the wet treatment using diluted hydrofluoric acid described in the following document 1!, the dry treatment using hydrogen plasma described in the following document 2!, and the dry treatment using hydrogen atoms (hydrogen radicals) described in the following document 3!.
1! G. S. Higashi et al., J. Appl. Phys. Lett., Vol.56, No.7, 1990, pp.656-658
2! A. Kishimoto et al., Jpn. J. Appl. Phys., Vol. 29, No.10, 1990, pp.2273-2276
3! T. Takahagi et al., J. Appl. Phys., Vol.68, No.5, 1990, pp.2187-2191
Among the above methods, the wet treatment using diluted hydrofluoric acid makes it possible to obtain a stable surface hardly reacting on other elements for a (111) plane of silicon. However, there is no stability for a (100) plane of silicon. Moreover, because of the wet treatment, fluorine may be left on the surface of a semiconductor wafer. Furthermore, it is difficult to connect a wet treatment apparatus with a dry treatment apparatus. Therefore, the dry treatment is desirable because it allows the apparatuses to easily connect each other.
The dry treatment using hydrogen plasma may damage the surface of a silicon substrate because high-energy particles collide with the surface.
The dry treatment using hydrogen radicals does not have the above problems. However, it is described in the above document3! that the treatment took a long time at the hour order. Therefore, this dry treatment cannot practically be used.
As another type of dry treatment, a method for removing a natural oxide layer by transforming hydrogen fluoride (NF.sub.3) and hydrogen (H.sub.2) into plasma is disclosed in the official gazette of Japanese Unexamined Publication (KOKAI) No. Hei. 2-77124. The inventors of the present invention. confirmed that a natural oxide layer was removed by this method. However, at the same time, the fact was found that the inner surface of a silica tube constituting a reaction chamber was etched and roughened.
It is an object of the present invention to provide a method and an apparatus for treating the surface of a semiconductor layer to shorten the time consumed for oxide layer removal and hydrogen termination by means of dry treatment, and moreover prevent the inner surface of a silica tube serving as a reaction chamber from roughening, and a method for fabricating a semiconductor device including the above steps.